Motor-vehicle transmission-gearing.



D. M. SMITH.

MOTOR VEHICLE TRANSMISSION HEARING. APPLICATION FILI-:n IIIAII` e, 1914.

1,177,826. I Patnted Apr. 4,1916.

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D. M. SMITH. MOTOR VEHICLE TRANSMISSION GEARIIIIG.

APPucATloN FILEDk MAR. 6, 1914.

1,177,826; y Patented JM1916.

3 SHEETS-SHEET 2.

THE COLUMBIA PLANOGRAPH co4. wAsHxNuToN, D. C.

' BLM. SMITH.

IIIOTOR VEHICLE TRANSMISSION SEAIIING.

MPLICATION FILEDKMAR. 6. 1914.

1,177,826. Patented Apr. 4,1916.

3 SHEETS-SHEET 3.

gif/755655,

Umrnn sfrarnsf DEMPSTER M. SMITH, 0F WASHINGTON, DISTRICTOF COLUMBIA.

Specification of Letters Patent. Y Patented Apr, 4, 1916 Application led March, 1914. Serial No. 822,902.

To all Iwhom t may concern.'

Be it known that I, Dniir'srnn M. SMITH, a citizen of the United States, residing at lllasliington, in the District of Columbia,

have invented certain new and useful Im- Y ing pinionto engage these gears selectively.

In previous structures, when the axle has carried two crown gears to be engaged by the same pinion and when the pinion is slidably mounted on a fixed axis, a neutral space, at least equal to the face width of the pinion, has been provided betweenthe gears. Hthin the limit of sizes permitted inra motor vehicle, this arrangement usually limits the number of gear ratios to two, since when a neutral space between the gears is provided the radial distancefaround the axle is such that it would ordinarily be impossiblerto provide more than two crown gears. According to this arrangement there is always considerable dilterence between the two ratios, due to the amount of neutral space necessarily provided. Ifthe two gears provided between them a space less than the width of the pinion, then in shifting the pinion from one gear to the other it would at sometime engage both of the gears at once and there would then be a breakage due to the different tangential speeds of the Other structures have provided for moving the crown gears axially, or for moving the pinion axis and by providing more than one pinion in connection 'with the movable axis, but all such arrangements introduce complications either in the mechanism itself or its operating means.

My invention provides means by which at least three ratios may be provided within the limits of motor vehicle construction in connection with a multiple crown gear fixed in respect to axial movement and with a single pinion sliding on a fixed axis.

The invention also provides means bv which the neutral space ordinarily provided between crown gears may be utilized to provide an additionaly drive ratio.

The invention also provides means for placing two gears of a cron-*n-gear-drive closer togetherthan the width of the pinion. The particular means employed consists 1n mounting one of the'crown gears loosely inrelation to its carrier in'respect to rotative movement and providing means for locking and unlocking this gear in relation'to Vits carrier. The gear is unlocked when the pinion isnshifted so as `to engage the free gear and one other gear at the same time and Vwhen the pinion is in full engagement Vwith the free gear that is lockedto its carrier for driving. lVhen the pinion engages another gear the free gear may be locked or unlocked, as maybe most convenient.

T he characteristics and advantages of, the invention will be further explained, so far as is necessary, in connection with a detailed vdescription of the accompanying drawing,

which shows one exemplifying embodiment of the invention.

Figure l is a view, mainly in horizontal section, ofbsufficient parts of a motor vehicle driving axle structure to show an embodiment 'of the invention. Fig. 2 is a side ele- ATENT OFFICE.

vation from the left, Vjust'withinthe casing j ofFig. 1. Fig.,3 is a diagrammatic view of connections ybetween the transmission gearing and other'parts of the'motor vehicle. Fig. 4 is a sectional detail of a free gear. Fig. 5 is a view of a modification in which only two crown gears are employed. In Fig. l, reference character 1v designates an axle casing or housing, and 2 designates a differential casing or housing revolubly mounted therein. A Vsuitable differential gearing is carried within housing 2 forvdifferential driving axle shafts 8 and l. Housing 2 carries crown gears 5, 6 and 7. At right angles to the rotative axis of the axle structure is a drive shaftor pinion shaft 8, mounted in bearings 9 and 10.V Slidably mounted on the pinion shaft` is pinion l1 engaging suitable splines or angularities 12 upon the shaft.

In ordinary practice, incombination with sliding pinion ll, two separated crown gears 5 and 7 would be employed, leaving between them a space where the gear 6 is located in the drawing. In shifting from gear 5 tc gear 7, therefore, the pinion would occupy al lioV ral space would have to be provided, and,

evidently, the diameter' of the axle structure I would in this way be greatly increased.- Evidently also, there is considerable dierence between the `ratios ofgears 5 and i and this difference might or might not he greater than pinion from gear 5 or gear 7 into engagement 'ith gear 6, because when the pinion engaged any tivo of these Gears at the same time, the different tangential `speeds Vof the gears would cause damage or breakage to the teeth, of the pinion or the' gears. t I overcome this difficulty by mounting gear 6 loosely in relation to theother gears and providing clutch means, exemplified by the sliding member 13, for connecting geary 6 rigidly with the ldiiferential housing when pinion 11 is in engagement With said gear and free from the other gears. When the pinion is being shifted so that it engages at the same time gear G and gear 7, or gear 6 and gear 5, the clutch means is operated so that gear 6 is free in respect to the other gears and the pinion. will then takethe rotative speed of the hired gear and will drive gear faster or slower, as the case may be, without unfavorable results. f

Referring more particularly to the .representative embodiment `here shovvn, the gear carrier 14: may be connected to housing 2 and gears 'and 7 may berigidly secured to this carrier. 'Loose gearblmay be formed upon ring 15 (see Fig. 4); llanges 16 on this ring engage under tlanges`17 on gears 5 and 7. @n the back of ring 15 is an annulus of clutch jaws or teethA 17. At each side of these teeth is` placed a bearing. or Wearing ring 18, lilling the space between the gear ring at the sides of the clutch teeth 17 and carrier 14, and providing a readily renewable bearing surface for the gear 6. This is only a detail which Will permit the easy formation of clutch teeth 17 upon the loose gear. Sliding member 13, to connect and disconnect the loose gear with its carrier, may be mounted on the differential housing, as shrivn. rlhis sliding member is Vprovided with one or more arms 19 passing through slots or channels 20, suitably formed in the carrier and in the 4body of gear 7. These arms carry clutch teeth 21 to cooperate with teeth 17 of the lcose ring. 1n many cases fairly close construction about the axle is necessary, and to permit the necessary movement of member-13 and its arm 19 the diii'erential housing mayneed to be slotted, as at 22, to accommodate these arms. In differential mechanism ordinarily used, there is, of course, considerable distance between the outer wall of the housing and the differen- Vmencesto engagethe teeth of Oear 5 or tial gears Within, and lthe easing may, of i course, be cut away at anypoint and arms 19 may extend Within-the limits of the casing@ i to any extent, so long they do not actuallyA touch the gears. it is, in tact, customary to vo` malte apertures through the difeientiall housing ininanycases, and provision of l moved' farther away from the axis of pinion 11, and inthis case such close design iii certain respects .vill be unnecessary.

Sliding member 13 in Fig. 1 isy shown in such position that teeth. 21 carried by arms v19engage teeth 17 of gear l6 and connect the gear rotatively with the di'derential housing. Pinion 11 is in engagement with the gear and drives it at the intermediate directratioz If itis desired to shift the pinion to .engage gear 5 or gear 7, sliding member 13 is moved toward the differential housing until clutch teeth 21 are free from teeth 17. Gear Gis thereupon rotatively free in relation to the;

other gears; pinion;11 is moved until it coml gc 7 g the 4pinion Will then rotate in accordance with the speed of rotation of the fixed'gear and gear 6l will bedriven idly at a speed corresponding to this rotative speed of the pinion. releases it from gear 6 and brings pinion in full engagement with gearL or gear 7, and drive may then be accomplished through Yeither of these gears, and it-is ofno consequence Whether gearlvG is again connected rotatively With its carrier or not.

It will be apparent that this invention is of value in any case Where it is desired to .place tivo croivn gears closer-together than the face Width of the pinion. For instance, suppose only tivo ratios were provided by means of a lixed gear. 5 and a loose gear G arranged as shovvn in Fig. 1. Gear 6 Nwould then be released in changing from one to Further movement ofthe pinion:

the other and would be connected with the carrier when the pinirn 11 drives it, as above described. Evidently, when tivo crown gears are employed,.it is immaterial which one is released When the pinion is shifted, i

ion shaft to be mounted with a fixed axis in f suitable bearings and permits the difierential housing and the crown gears to revolve in a xed plane, and, yet, by very simple means, provides at leastthree different di-v rect drive ratios and utilizes the space'ordinarily lost between the highest and lowest ratio gears. Irovision is made for employing bearing 10 of sufficient size at the rear end of the/pinion shaft. Although the particular embodiment shows in many respects standard and approved practice, it is not to be understood that I limit myself to details in any way, except as claimed hereafter.

Various w'ays of shifting pinion 11 and accomplishing release of gear 6 at the proper time may be employed. Probably the practical success' of the invention depends in some applications upon a successful controlling arrangement,and I, therefore, show one suitable form of controlling means, al-V though, evidently, various means may be employed. Shifter 13 might in some c ases be ccntrolled by a separate lever and might be normally 'in inactive position, so that yactively only with gears 5 and 7.

gear 6 would be normally loose. Pinion 11 would then be controlled by its own lever and in ordinary operation would coperate When shifted to engage Igear 6 for active driving, however, shifter 13xwould be manipulated by its lever to lock gear 6 to the carrier, and the driver would have to pay particular attention to releasing this gear before he shifted the pinion. But, in combination with other necessary features ofk a motor car, simple autcmatic -means may be provided for releasing the loose gearat the proper time, and I here show one such means. Fig. 3

' shows, in a diagrammatic way, a motor M,

clutch C, clutch-lever L,v operating the clutch by'means of fork F, and a. link 25 connected to the arm 26 on the clutch lever shaft. vShifter 13 may be moved by yoke 27 having a rod or arm 28 actuated by bellcrank arm 29 carried by the bell-crank shaft 30 extending up through the casing and carrying outside the casing an arm 31 bearing a stud The rear end of link 25 has a slot 33 coperating with stud 32. Bell-crank shaft 30 may be urged by spring 34 engaging arm 35 insuch direction that shifter 13 and its clutch teeth are normally in active position to lcck gear 6 to its car rier. Pinion 11 is moved by yoke 36 can ried by shifting rod 37, and this rod is moved by any suitable lever mechanism notparticularly shown. Near the rear end, rod 37 carries a notch 38 coperating with the end 39 of shifter rod 28.

Supposing pinion 11 and shifter 13 to be in the position shown in Fig. 1, and the clutch C to be engaged as shown in Fig.V 3, to shift pinion 11 clutch C should first be released by depressing pedal lever L. At about the time the clutch is releasedV the end of slot 33 encounters stud 32, and, through the 'bell crank, shifter-v rod 28 is moved against the pull of spring 34 suiiciently to release clutch teeth'21 from gear 6, andat about the sameY time the end 39 of rod 28 is freed from notch 38 of shifter-rod 37.

Gear 6 is then loose in relation to its carrier and the pinion may be shifted by means of rod 37 to engage either gear 5 or gearV 7 with perfect safety, as previously eXplained.`

so by the engagement ofdetent 39 withrod i 3 7. He would be prevented fromy moving rod 37V to shift the pinion if any connection between the clutch pedal and shifter 13 vwere disarranged. In fact., he can only shift thev pinion when shifter 13 is moved to free gear 6, and it is then, of course, 4safe to move the pinion. If no other notches are provided in rod 37, detent 39 on the end of shifter-rod` 28 will ride upon the surface of the rod, and gear 6 will remain unlocked until pinion 11 is again brought back into full registry with gear 6. In this case, the actuation of the clutch lever L will not affect the unlocking mechanism 28, etc., except at such times as the pinion is in vvengagement with gearV 6.

This would not prevent'the careless drivervv from shifting the pinion from gearV 5 or gear 7 into engagement with gear 6 Vwithout releasing the main clutch C. No breakage of the pinion or gear'teeth would probably result from this carelessness, but damage to teeth 21 and 17 might result, because when the pinion reached full -registry with gear 6, teeth 21 would snap into engagement with teeth 17 while the engine was actively driving the pinion. This might cause damage. Sucha contingency is possible, however, in any transmission arrangement employing positive teeth either in the gears or in clutches unless an interlock between the friction clutch and the gear is employed. My invention may provide for this contingency by providing additional notches 38a and 38", shown in dotted lines in Fig. 1. These notches correspond, respectively, to the pinion 11 when it is in engagement with gear 5 and gear 7. and, evidently, in either ease detent 39 will engage with the corresponding notch and hold the pinion in fixed position until the friction clutch is again released. This would involve the engagement of teeth 21 with teeth 17 of the loose gear but such an action will have -no active effect and would not be objectionable ordinarily.

In casesr where it is noty considered desirable to connect the gear releasing mechanism with'the main clutch, a single lever maybe so constructed and arranged that it ated in Fig. 2.

will effect the proper disengageinentv oi'the free gear and shifting of the pinion 11. So many different controlling arrangements may be employed that it is not considered necessary to show more than one in the present case.

In F ig. 1, the level of rods 87 and i8 and bell-crank arm 29 is supposed to be above the plane or" shaft 8 and the axle. But these parts are all shown in one view for greater facility in understanding the operation of the mechanism. Many different arrangements oi the controlling mechanism may be employed without aecting the principles involved.

As shown in F ig. 2,' arms 19 'of lshifter 13 are caused yto .revolveV in unison with the differential housing vby engagement of these arms with the sides of slotsOof carrier 11i, clearancer between the arms and walls ot the slots being purposely somewhat exaggertherwise, thesleeve of the housing carrying shifter 13 might be splined to provide rotative, sliding connection. between the parts.

F ig. 5 shows an embodiment of the invention in which. two gear ratios are provided by means or two crown gears and one pinion. In this arrangement the inner crown gear 6 is provided with inward clutch teeth 5() and with these' teeth va sliding jaw clutch 51 splined vto thediii'erential sleevecoperates. The clutch arrangement for connecting and disconnecting the free gears Ga is in this case somewhatsimpler than in Figi. rihis form of the i vention will be advantageous when two direct `ratios are required and .when by the ordinary arrangement the diameter of the largest crown gear would'be too great or when by the ordinary arrangement the diiierence between Vthe ratios of the two gears would be .too great, owing to the necessity oi' providing between them a space equal to the face width of the pinion.

Evidently, my invention is not limited toV two or three crown gears but any plu ality of crown gears may be employed, it only being necessary that when the pinion lis shifted to engage twoo'f them at once one of these two shall be movable in relation to the other to prevent damage to the teeth'in shifting.

A good many dierent ways of connecting and disconnecting the free gear with its carrier may be provided. I consider it broadly new to provide in connection with an axle and a shiftingpinion two crown gears closer together than the face width oit' the pinion and means to release one of the gears when the pinion is shifted.

1 claim 1. In a motor vehicle, the combination ot angles to the gear axis, and adapted to engage both of said gears simultaneously in shitting, and means for connecting and dis-` connecting the freegear with the axle.

3. 1n ay motor vehicle, the combination of an axle, two crown gears fixed thereon, a third Y crown gear between the vlixed gearsv and:

loose in relation to the axle, a pinion adaptedto enoagesaid crown gears selectively and to engage two 'of them at once in sli-ifting, anl means tor connecting anddisconnectinggsaid free gear with the axle..

4:. ln a motor vehicle, the combination of an axle, a crown gear tast thereon, acrown gear loose thereon, a sliiftable pinion, means for looking and unlocking the loose crown gear, and an interlocking connection betweensaid means and-said pinion whereby the pinion can only be shifted when said locse gear is free. i

5. ln a motor vehicle, the combinationy of an axle, a crown gearfast thereoinaj crown gear loose thereon, shittable clutch means carried by the' axle for engaging and disengaging the loose gear, and a shiftable pinion having` a `fixed axis at right angles to the gear axis, said pinion being arranged to engage said crow-n gears selectively and to engage two of them simultaneously in shift-V ing.

6. In a motor vehicle, the combination of an axle, a plurality of crown gears thereon, means for connecting and disconnecting4 one of the' gears rotatably with the axle,f

and a shiftable ,pinion adapted lto engage the crown gears selectively and to engagey two of them simultaneously in shifting.y

7. ln` a motor vehicle, the combination Vof an axle. a plurality of crown gears thereon,

means for connecting and disconnecting'cne.

of the gears rotatably with the axle, a shiftable pinion adapted Yto engage the crown gears selectively and to engage two oithemV simultaneously inshifting, and an interlocking device to insure `that the releasable crown gear is in disconnected condition wien the pinionis in simultaneous engagement with it and another `of ther crown gears.`

DEMPSTER M. SMlTI-Lv Witnesses A. M. PAnKiNs, M. A. Toom Copies of this patent may be obtained for nve cents each, `by addressing the "Commissioner offl'a'tents,

i Washington, D. C. 

